Adjusting device for optical system of rear projection television

ABSTRACT

An adjusting device of a rear projection television comprises a supporting seat, a first supporting frame, a pivoting element pivoted on the fist supporting frame, a second supporting frame and an adjusting unit. The first supporting frame is combined on the supporting seat and includes a through first screw hole and a through second screw hole. The second supporting frame and the first supporting frame are disposed at intervals and pivotally connected on the pivoting element. The second supporting frame is rotated relatively to the first supporting frame and is unparallel to first and second rotating directions. The adjusting unit comprises a first positioning element and a second positioning element; the first and the second positioning elements are respectively through the first screw hole and the second screw hole to attach on the second supporting frame.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an adjusting device, and more particularly to a device for adjusting an angle of an optical system of a rear projection television.

2. Description of Related Art

The main principle of a rear projection television such as a CRT-based rear projection television or a microdisplay-based rear projection television is to enlarge a projecting beam through an optical system to project an image on a screen of the television. Therefore, the optical system in the television must be assembled accurately so that images projected on the screen of the television are not deformed and the quality and clearness of the images are maintained.

For allowing the fine adjustment to be processed on the projection device under a situation that images are aberrant on the rear projection television to maintain the relative position between each optical elements and a projection angle, such as Taiwan New Utility Pat. No. 566,792 entitled as “Projection Adjusting Device” is proposed. Please refer to FIGS. 1 and 2. A mounting seat 12 and an adjusting frame 13 of a projection-adjusting device 1 disclosed in the patent are pivotally connected mainly through a ball bearing 11 and the adjusting frame 13 is taken as an indefinite point, three adjusting bolts 14 passed through the screw holes 131 and propped against the mounting seat 12 and formed as a plane arrangement are rotated to change the distances between the mounting seat 12 and the adjusting frame 13 at the positions of the adjusting bolts 14 so as to achieve the adjustment of the angle of a reflecting mirror 2 on the mounting seat 12.

The production cost of the conventional projection-adjusting device 1 is rather expensive owing to large numbers of the constituting components, and much more time must be spent to process the assembly among the components. In addition, the ball bearing 11 is a ball supporting that is rotated arbitrarily in a space. When two of the adjusting bolts 14 are adjusted to cause the mounting seat 12 to rotate on a plane, the mounting seat 12 produces a rotating component in a direction perpendicular to the plane to induce the orientation of the reflecting mirror 2 to be deviated such that twisted images or images projected over the display range of the television screen (not shown in the figure) are caused. This increases the difficulty on the adjustment and reduces the good product ratio. Besides, the ball bearing 11 is fixed on the mounting seat 12 with a single point. The point contacting portions of the ball bearing 11 and the mounting seat 12 is easy to yield deformation owing to the torsion acted thereon after a long term use so that the activity ability of the ball bearing 11 is indirectly influenced.

SUMMARY OF THE INVENTION

Therefore, one object of the present invention is to provide an adjusting device capable of simply adjusting a reflecting angle of an optical system of a rear projection television.

Another object of the present invention is to provide a simply structured and low-cost adjusting device for an optical system of a rear projection television.

Still another object of the present invention is to provide an adjusting device for an optical system of a rear projection television, capable of preventing the torsion from influencing the adjustment function.

For attaining to the objects mentioned above, an adjusting device for an optical system of a rear projection television according to the present invention is installed in a television housing and used for adjusting an reflecting angle formed from the optical system toward a television screen. The adjusting device comprises a supporting seat, a first supporting frame, a pivoting element, a second supporting frame and an adjusting unit. The supporting seat is attached on the television housing, and two opposite sides of the first supporting frame are respectively rotatably connected to the supporting seat and the pivoting element; the first supporting frame has a first supporting surface facing the television screen and a second supporting surface opposite to the first supporting surface on which a first screw hole and a second screw hole passing through the first supporting surface and the second supporting surface are formed separately. The second supporting frame and the first supporting frame are disposed at intervals and pivoted on the pivoting element. The optical system is attached on one side of the second supporting frame opposite to the pivoting element. The second supporting frame is rotated relatively to the first supporting frame at unparallel first and second rotating positions. The adjusting unit comprises a first positioning element and a second positioning element; the first and the second positioning elements respectively pass through the first screw hole and the second screw hole and are attached on the second supporting frame. The first positioning element is moved between a first extending position close to the television screen and a first retracting position away from the television screen, and the second positioning element is moved between a second extending position close to the television screen and a second retracting position away from the television screen.

When the first positioning element is moved from the first retracting position toward the first extending position, the second supporting frame is rotated along a first rotating direction. When the first positioning element is moved from the first extending position toward the first retracting position, the second supporting frame is rotated along a direction reverse to the first rotating direction; when the second positioning element is moved from the second retracting direction toward the second extending position, the second supporting frame is rotated along a second rotating direction; when the second positioning element is moved from the second retracting position toward the second retracting position, the second supporting frame is rotated along a direction opposite to the second rotating direction. Whereby, the reflecting angle of the optical system is adjusted.

According to the adjusting device for an optical system of a rear projection television of the present invention, the reflecting angle of the optical system is simply adjusted through the assembly of a few components. Not only the time for assembly, adjustment and maintenance is reduced, but also the production cost is relatively lowered. Furthermore, the use of the pivoting element replaces single-point-contacting ball bearing can also prevent torsion from influencing the adjusting device. In addition, through the combination of two positioning elements and a pivoting element, three directional synchronous rotations do not happen to the optical system to avoid the interference on the adjustment operation.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is more fully understood by reference to the following description and accompanying drawings, in which:

FIG. 1 is a perspective view, showing a conventional projection-adjusting device;

FIG. 2 is a side cross sectional view, showing a conventional projection-adjusting device;

FIG. 3 is a schematic cross sectional view, showing an adjusting device for an optical system installed in a rear projection television according to the present invention;

FIG. 4 is a perspective view, showing an adjusting device for an optical system of a rear projection television of a preferred embodiment according to the present invention;

FIG. 5 is an exploded view, showing an adjusting device for an optical system of a rear projection television of a preferred embodiment according to the present invention;

FIG. 6 is a partly vertical cross sectional view, showing an adjusting device for an optical system of a rear projection television of a preferred embodiment according to the present invention;

FIG. 7 is a view similar to FIG. 6, showing that a first positioning element is rotated toward a second supporting frame to cause the second supporting frame to be rotated along a first rotating direction;

FIG. 8 is a view similar to FIG. 6, showing that a first positioning element is rotated away from a second supporting frame to cause the second supporting frame to be rotated along a direction opposite to a first rotating direction;

FIG. 9 is a partly side cross sectional view, showing an adjusting device for an optical system of a rear projection television of a preferred embodiment according to the present invention;

FIG. 10 is a view similar to FIG. 9, showing that a second positioning element is rotated toward a second supporting frame to cause the second supporting frame to be rotated along a second rotating direction; and

FIG. 11 is a view similar to FIG. 9, showing that a second positioning element is rotated away from a second supporting frame to cause the second supporting frame to be rotated along a direction opposite to a second rotating direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the detailed description of the present invention is done, it must be noticed that same components is expressed with same component numbers in the following description.

Please refer to FIG. 3. In a preferred embodiment according to the present invention, an adjusting device 400 for adjusting a reflecting angle of an optical system 34 is installed in a television housing 31 of a rear projection television 3. However, application range thereof comprising other different occasions such as the level positioning and the perpendicular positioning of a measurement instrument such as a spirit level (not shown in the figure) cannot be disclosed one by one in the description; a person skilled in the art without doubt has no problem to apply it in the similar condition. The rear projection television 3 comprises the television housing 31, a light source 33 installed in the housing 31, the optical system 34 installed in the housing 31 and a television screen 35 inlayed on the housing 31. The optical system 34 in the current embodiment is a reflecting mirror 34, but it is another component with similar functions in another practice mode.

Please refer to FIGS. 4 and 5. The adjusting device 400 comprises a supporting seat 4, a first supporting frame 5, a pivoting element 6, a second supporting frame 7 and an adjusting unit 8. The supporting seat 4 comprises two triangle-shaped supporting elements 41 disposed at intervals; two adjacent edges of each supporting element 41 are respectively correspondingly connected with a connecting seat 33 of a rear projection television 3 and the first supporting frame 5 to cause the first supporting frame 5 to be fixed on the housing 31 of the rear projection television 3. The shape of the cross section of the supporting element 41 (not shown in the figure) adopted in the supporting seat 4 is not limited to be L-shaped; only that the first supporting frame 5 is fixed on the connecting seat 33 of the rear projection television 3 is enough, and a manner such as screw fixing, welding or forming into one body with the first supporting frame is used for connecting the supporting element 41 with the first supporting frame 5.

The first supporting frame 5 comprises a first main body 51. The first main body 51 has a first supporting surface 511 facing a television screen 35 and a second supporting surface 512 opposite to the first supporting face 511, and a first screw hole 52 and a second screw hole 53 passing through the first supporting surface 511 and the second supporting surface 512 are respectively formed in the middle of two adjacent ends of the first main body 51. A first connecting element 91 is combined on the first supporting surface 511 of the first main body 51. The longitudinal direction of the first connecting element 91 is levelly disposed (parallel to X-axis direction) and a through hole 911 is formed at the center thereof. Two raised ears 912 protruding toward the television screen 35 are respectively disposed on upper and lower sides of the through hole 911. Here, the first main body 51 is a rectangle, but it may be another shape such as a polygon.

The pivoting element 6 comprises a hollow cuboid 61, a through hole 62 is disposed in the center of each edge of the cuboid 61. The cuboid 61 is inlayed between two first raised ears 912 of the first connecting element 91 and pivotally connected to the first raised ears 912 with the upper and the lower through holes 62.

The left and the right through holes 62 of the cuboid 61 are pivotally connected to a second connecting element 92. The longitudinal direction of the second connecting element 92 is disposed along a perpendicular direction (parallel to Z-axis direction). Two second raised ears 921 pivotally connected to the cuboid 61 are respectively disposed at the left and the right sides of the second connecting element 92. One side of the connecting element 92 opposite to the second raised ears 921 is connected onto the second supporting frame 7 to cause the second supporting frame 7 to be moved together to rotate along a same direction when the second connecting element 92 is rotated.

The second supporting frame 7 comprises a second main body 71 and a surrounding wall 72 extending around the circumference of the second main body 71 in a direction opposite to the second connecting element 92 to allow the second main body 71 and the surrounding wall 72 to define a accepting room 73 in which a reflecting system 34 (reflecting mirror 34) of the rear projection television 3 is inlayed. Because the second supporting frame 7 and the first supporting frame 5 are rotatably connected through the pivoting element 6, the second element 7 is pivotally rotated relatively to the first supporting element 5 between a first rotating direction (rotated around an axis parallel to the Z-axis in the embodiment) and a second rotating direction (rotated around an axis parallel to the X-axis in the embodiment). For illustrating conveniently, the projections of the axis for rotating along the first rotating direction and the axis for rotating along the second rotating direction on the X-Z plane (a proper plane) are perpendicular to each other, but in other conditions, only that they are not parallel to each other is enough.

The adjusting unit 8 comprises a first positioning element 81, a second positioning element 82, and an elastic element 83 positioned between the first supporting frame 5 and the second supporting frame 7. The first positioning element 81 and the second positioning element 82 are screws in this embodiment, but they may be T-shaped bolt or anything else. The first positioning element 81 and the second positioning element 82 respectively pass through a first screw hole 52 and a second screw hole 53 and then are propped against the second supporting 7. The first positioning element 81 is moved between a first extending position close to the television screen 35 and a first retracting position away from the television screen 35, and the second positioning element 82 is moved between a second extending position close to the television screen 35 and a second retracting position away from the television screen 35. The elastic element 83 is a spiral spring in the embodiment, but it may be an elastic plate or anything else. Two ends of the elastic element 83 are respectively connected to the first supporting frame 5 and the second supporting frame 7, and installed opposite to an included angle formed by two sides on which the first screw hole 52 and the second screw hole 53 are disposed. A plane is formed among the first positioning element 81, the second positioning 82 and the elastic element 83 to cause the elastic element 83 to form couples respectively with the first positioning element 81 and the second positioning element 82 to reposition the second supporting frame 7 constantly. The pivotal connections of pivoting element 6 with the first supporting frame 5 and the second supporting frame 7 are attained through the first connecting element 91 and the second connecting element 92. When pivoting elements (not shown in the figure) having functions like the first raised ears 912 and the second raised ears 921 are respectively installed on the first supporting frame 5 and the second supporting frame 7, the first connecting element 91 and the second connecting element 92 are replaced so that the number of the needed components is simplified. Besides, although the accepting room 73 defined on the second supporting frame 7 through the surrounding wall 72 is used for inlaying the optical system 34 therein, a plurality of clamping elements (not shown in the figure) installed on the circumference of the second supporting frame 7 can also be used for fixing the optical system 34.

Furthermore, after the first positioning element 81 and the second positioning element 82 pass through the first screw hole 52 and the second screw hole 53, they are screwed in a third and fourth screw holes on the second supporting frame 7 (not shown in the figure) respectively corresponding to the first screw hole 52 and the second screw hole 53. When the first positioning element 81 and the second positioning element 82 are moved, the second supporting frame 7 is pushed or towed to rotate so as to achieve the object of the adjustment, the elastic element 83 is omitted at this time. On the other hand, the number of the elastic element 83 is a plural number. When the number of the elastic elements is two, they are disposed on the ends of opposite sides where the first screw hole 52 and the second screw hole 53 are disposed. The first screw hole 52 and the second screw hole 53 are not limited to be disposed at the middle of each end.

As FIGS. 6, 7 and 8 show, when the first positioning element 81 revolves toward the second supporting frame 7 (i.e. moves from the first retracting position to the first extending position), one end thereof propped against the second supporting frame 7 push the second supporting frame 7 to cause the pivoting element 6 to rotate relatively to the first supporting frame 5 to move the second supporting frame 7 together to pivotally rotate along the first rotating direction (i.e. a rotating axis parallel to the Z-axis direction), the elastic element 83 is compressed by a force to generate a recovering force at this time. When the first positioning element 81 is revolved outward away from the second supporting frame 7 (i.e. moved from the first extending position to the first retracting position), the second supporting frame 7 is moved together owing to the rotation of the pivoting element 6 is driven with a recovering force existing in the elastic element 83 to cause the second supporting frame 7 to pivotally rotate along a direction opposite to the first rotating direction (i.e. a rotating axis is parallel to the -Z-axis direction).

As FIGS. 9, 10 and 11 show, when the second positioning element 82 is revolved toward the second supporting frame 7 (i.e. moved from the second retracting position to the second extending position), one end thereof propped against the second supporting frame 7 pushes the second supporting frame 7 to cause the second supporting element 7 to be rotated pivotally along a second rotating direction (i.e. a rotating axis is parallel to the X-axis direction), the elastic element 83 is compressed by a force to generate a recovering force at this time. When the second positioning element 82 is revolved outward away from the second supporting frame 7 (i.e. moved from the second extending position to the second retracting position), the second supporting frame 7 is pivotally rotated along a direction opposite to the second rotating direction (i.e. a rotating axis is parallel to the -X-axis direction) owing to the recovering force of the elastic element 83.

When the images generated from the light source 32 of the rear projection television 3 are amplified on the television screen 35 through the optical system 34, if the deviation is yielded, a user can adjust the reflecting angle of the optical system to eliminate the aberration and maintain the clear projection quality according to the action relationship among the positioning elements 81, 82 and the second supporting frame 7.

To sum up, the balance of the couples among the positioning elements 81 and 82 disposed on a plane and the elastic element 83 is used in the adjusting device 400 for the optical system 34 of the rear projection television 3 according to the present invention to attain to the adjustment object of the optical system 34. Therefore, the production cost is reduced owing to the reduction of components, and the assembly complexity and the combination time are broadly lowered down. Furthermore, the fine adjustment between the positioning elements 81 and 82 is used to cause the optical system 34 only to rotate on a plane and not to cause a complex three-dimensional rotation so that the adjustment is simplified to achieve a complete control and the problem such as image distortion is not generated. On the other hand, a connection area between the pivoting element 6 and the second supporting frame 7 is bigger than the pivotal connection type of the ball bearing of the conventional adjustment device so that the stress concentration is reduced. Abrasion generated at a pivoting place and then influencing the adjustment mechanism is avoided, and the product life is extended, i.e. the objects of the present invention are accurately attained.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. 

1. An adjusting device for an optical system of a rear projection television, the adjusting device being installed in a television housing for adjusting a reflection angle of the optical system toward a television screen, the adjusting device comprising: a supporting seat combined on the television housing; a first supporting frame combined on the supporting seat, the first supporting frame having a first supporting surface facing the television screen and a second supporting surface opposite to the first supporting surface, a first screw hole and a second screw hole passing through the first supporting surface and the second supporting surface and separated from each other being formed thereon; a pivoting element pivotally connected on the first supporting frame; a second supporting frame separated from the first supporting frame with an interval and pivotally connected on the pivoting element, one side opposite to the pivoting element being connected with the optical system and being rotated relatively to the first supporting frame along unparallel first and second rotating directions; and an adjusting unit including a first positioning element and a second positioning element, the first positioning element and the second positioning element respectively movably passing through the first screw hole and the second screw hole and being attached to the second supporting frame, the first positioning element moving between a first extending position close to the screen and a first retracting position away from the screen, and the second positioning element moving between a second extending position close to the screen and a second retracting position away from the screen; when the first positioning element is moved from the first retracting position toward the first extending position, the second supporting frame rotating along the first rotating direction, when the first positioning element is moved from the first extending position toward the first retracting position, the second supporting frame rotating along a direction opposite to the first rotating direction, and when the second positioning element is moved from the second retracting position toward the second extending position, the second supporting frame rotating along the second rotating direction, when the second positioning element is moved from the second extending position toward the second retracting position, the second supporting frame rotating along a direction opposite to the second rotating direction; whereby, a position of the optical system is adjusted.
 2. The adjusting device according to claim 1, wherein the adjusting unit further comprises an elastic element, both ends of the elastic element are respectively connected to the first supporting frame and the second supporting frame to cause the second supporting frame to reposition constantly.
 3. The adjusting device according to claim 2, wherein the elastic element is spring.
 4. The adjusting device according to 2, wherein the number of the elastic elements is two, the first supporting frame is a rectangular plate, and the first screw hole, the second screw hole and the elastic elements are respectively disposed at each end of the rectangular plate.
 5. The adjusting device according to claim 2, wherein the first screw hole, the second screw hole and the elastic element are respectively disposed in the middle of each end of the first supporting frame.
 6. The adjusting device according to claim 1, wherein projections of a rotating axis as a basis of a rotation along the first rotating direction and a rotating axis as a basis for a rotation along the second rotating direction on a proper plane are perpendicular.
 7. The adjusting device according to claim 1, further comprising a first connecting element, the first connecting element being attached on the first supporting frame, and a first raised ear being disposed at each of two opposite ends thereof to pivotally connect the first supporting frame on the pivoting element.
 8. The adjusting device acãording to claim 1, further comprising a second connecting element, the second connecting element being attached on the second supporting frame, and a second raised ear being disposed at each of two opposite ends to pivotally connect the first supporting frame on the pivoting element.
 9. The adjusting device according to claim 1, wherein the first supporting frame is a rectangular plate, the first screw hole and the second screw hole are respectively disposed on two adjacent ends of the first supporting frame, the number of the elastic element is one and one end thereof is connected opposite to an included angle of the adjacent ends.
 10. The adjusting device according to claim 1, wherein the first positioning element and the second positioning element are screws.
 11. The adjusting device according to claim 1, wherein the optical system is a reflecting mirror. 